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Checkley, DM, Dagg MJ, Uye S.  1992.  Feeding, excretion and egg production by individuals and populations of the marine, planktonic copepods, Acartia spp. and Centropages furcatus. Journal of Plankton Research. 14:71-96.   10.1093/plankt/14.1.71   AbstractWebsite

Diel variations in vertical distribution, gut pigment content, ammonium excretion and egg production were investigated for adult females of Acartia erythraea and A. pacifica in the vertically mixed Inland Sea of Japan and Centropages furcatus in the stratified, neritic Gulf of Mexico. Gut pigment content and egg production rate were maximal at night and ammonium excretion was maximal during the daytime. Neither A. erythraea nor A. pacifica adult females showed an apparent diel migration, but the former were highly concentrated in the sur-face layer during the afternoon. In contrast, C. furcatus adult females showed a clear diel migration, residing immediately above the bottom during the daytime and being concentrated between 10 and 25 m depth during the night-time. Individual-based data on gut content and excretion and egg production rates were combined with vertical-distribution data to calculate population values. In the Inland Sea of Japan, the resultant pattern for Acartia spp. reflected the diel variation in physiological rates and even distribution of adult females, except for the afternoon, surface aggregation of A. erythraea. In the Gulf of Mexico, the pattern for C. furcatus reflected largely the diel variation in each rate process and the heterogeneous distribution of adult females in the water column. Elevated nocturnal feeding activity of these copepods may be due to an endogenous rhythm. The daytime maximum in ammonium excretion and night-time maximum in egg production rate indicated approximate half-day and day time lags, respectively, after the intake of food until its conversion into dissolved excreta and released eggs.

Checkley, DM.  1980.  Food limitation of egg production by a marine, planktonic copepod in the sea off Southern California. Limnology and Oceanography. 25:991-998. AbstractWebsite

The in situ rate of egg production (B) and female size of Paracalanus parvus, a particle-grazing copepod, water temperature, and the concentrations of chlorophyll a and particulate nitrogen were measured in 31 collections from the euphotic zone of the sea off southern California. B was correlated positively with chlorophyll a and female size and negatively with temperature. A multiple regression of log B on chlorophyll a, particulate nitrogen, female size, and temperature accounts for44% ofthe variationin log B. B was predicted best by an empirical function of food concentration when the food available in nature was considered to be phytoplankton rather than of all types of particulate matter >5 ยต.An index of immediate food limitation was derived from laboratory data as a function of food concentration. When applied to extensive measurements of chlorophyll a in the euphotic zone, this index indicates that Paracalanus was often food limited and that food limitation increased along an onshore-offshore transect. Paracalanus was rarely food limited in Santa Monica Bay.